Salix sitchensis vs Sitka willow

Salix sitchensis and Sitka willow both are nouns.

Word	Noun	Adjective	Verb	Adverb
Salix sitchensis	Yes	No	No	No
Sitka willow	Yes	No	No	No

As nouns, Salix sitchensis and Sitka willow are synonyms defined as:

Salix sitchensis and Sitka willow: small shrubby tree of western North America (Alaska to Oregon)

Other synonyms of Salix sitchensis include silky willow.

Salix sitchensis (noun)	Sitka willow (noun)
small shrubby tree of western North America (Alaska to Oregon)	small shrubby tree of western North America (Alaska to Oregon)